fix: need to look for folder in src

poetry/repositories/installed_repository.py

@@ -69,6 +69,11 @@ class InstalledRepository(Repository):
                                 # this is required to handle pathlib oddity on win32 python==3.5
                                 path = lib.joinpath(path)
                         paths.add(path)
+
+        src_path = env.path / "src" / name
+        if not paths and src_path.exists():
+            paths.add(src_path)
+
         return paths
 
     @classmethod